Problem: Simplify the following expression: $ n = \dfrac{-3}{5} - \dfrac{t - 1}{6} $
Explanation: In order to subtract expressions, they must have a common denominator. Multiply the first expression by $\dfrac{6}{6}$ $ \dfrac{-3}{5} \times \dfrac{6}{6} = \dfrac{-18}{30} $ Multiply the second expression by $\dfrac{5}{5}$ $ \dfrac{t - 1}{6} \times \dfrac{5}{5} = \dfrac{5t - 5}{30} $ Therefore $ n = \dfrac{-18}{30} - \dfrac{5t - 5}{30} $ Now the expressions have the same denominator we can simply subtract the numerators: $n = \dfrac{-18 - (5t - 5) }{30} $ Distribute the negative sign: $n = \dfrac{-18 - 5t + 5}{30}$ $n = \dfrac{-5t - 13}{30}$